Hi Niyongira,
To convert the ZD based APs to Stand alone, they have to be accessed individually via CLI and enable their web access using command "set https enable" and they have to be upgraded to Standalone firmware after the upgrade all the APs have to be individually configured.
Another method is, if you have all as R310 AP then they can be used with Unleashed (New Controller less platform) firmware please upgrade one AP with Unleashed firmware it will act as Master(Controller) and configure the SSIDs on them, then please upgrade all the others with Unleashed firmware the later upgraded APs would connect to the first one without any effort if all the APs are in L2.
Hope it helps.
Regards,
Abilash PR